Dehns have previously discussed the concept of plausibility and how much experimental data is needed for patent applications in Europe, which is relevant to both sufficiency and inventive step. In an ideal world all the relevant data would be contained in the application as filed. However, this is not always possible, particularly if new prior art is found during prosecution that necessitates the formulation of new comparative data to support an inventive step.

The approach taken by the EPO to the assessment of late-filed evidence (e.g. experimental data not included in the original application) is currently being considered by the EPO Enlarged Board of Appeal under referral G2/21.

The EPO Enlarged Board of Appeal will hear G2/21 on 24 November 2022, but in the meantime the Enlarged Board of Appeal have issued their preliminary (and non-binding) opinion.

The three questions referred to the Enlarged Board of Appeal can be reasonably be summarised as:

  1. Should evidence showing an effect (i.e. new experimental data) be disregarded if it is not in the application as filed and the new evidence is the only evidence of any effect?
  2. If so, is this still the case if the effect is plausible based on information in the patent application or the common general knowledge?
  3. Or can the evidence be taken into account simply if there was no reason at the filing date to consider the technical effect implausible?

In their preliminary opinion the Enlarged Board appear to strongly suggest that evidence cannot be disregarded as a matter of principle, meaning the answer to the first question would be ‘no’.

Nevertheless, the Enlarged Board have also considered questions (2) and (3), and have indicated that they consider that new evidence showing an effect should be taken into account where there would have been no significant reason for the skilled person to doubt the effect (i.e. where the claimed effect was not implausible). This indicates that the Enlarged Board currently consider that the answer to both questions (2) and (3) should be ‘yes’.

The Enlarged Board therefore seem to suggest that the test for considering new data should be the more lenient one suggested by the referring Board, namely that evidence supporting a technically effect can be taken into account simply if there was no reason at the filing date to consider the effect implausible. They do, however, warn that the technical effect relied on should be encompassed by the technical teaching of the original application and embody the same invention.

If this preliminary opinion matches the final decision then this will be welcomed by applicants and patentees, as being unable to rely on late-filed evidence in support of inventive step would undoubtably make establishing an inventive step harder, particularly in view of new prior art. However, this is simply a preliminary opinion and it will be interesting to see whether the Enlarged Board change their opinion before or at the hearing later this month.

Finally, it is worth noting that the Enlarged Board also suggest that their decision will be limited to the concept of plausibility as it relates to inventive step, and not sufficiency, despite the same concept of plausibility being relevant to both issues.